DNA microarray technology is an important new tool for studies in functional genomics that has the potential to dramatically change the way that biomedical research is conducted. Thousands of human cDNAs, and eventually the entire human genome, can now be spotted on a microscope slide-sized chip. Changes in patterns of gene expression from normal and diseased or treated cells can be rapidly detected by using flourescent probes to differentially label the expressed gene products. The technology is already being used in human genetic research, disease profiling, drug discovery and many other aspects of basic and translational biomedical research. In order to make this technology available to investigators at the Arizona Health Sciences Center at the University of Arizona we have established a core resource whose objectives are: 1) to fabricate the DNA microarrays; 2) to assist investigators with sample preparation and hybridization; and, 3) to provide bioinformatics support for analysis of the results. Functions 2) and 3) have already been established. The feasibility of function 1) has been demonstrated through the use of borrowed first generation equipment. We are requesting an integrated equipment package comprising a second generation robotic high density printer for preparing the arrays, a second generation DNA microarray reader, and equipment for bioinformatics and automated hybridizing equipment. This equipment will, in the short term, benefit investigators at the Arizona Health Sciences Center, with current grant support from the NIH of almost 14.5 million dollars direct costs per year and, in the long term, will introduce and enable investigations in DNA microarray throughout the University of Arizona.